Lock joint friction electrical connecter



Oct. 13, 1936. v. POLIMENI LOCK JOINT FRICTION ELECTRICAL CONNECTERFiled Jan. 6, 1953 INVENTOR.

Patented Oct. 13, 1936 UNITED STATES PATENT OFFICE.

Vincent Polimeni, Elmhur'st, N. Y. Application lanuary c, 1933, SerialNo. 650,490

3 Claims. (01. 173-301) This invention relates to improvements inelectrical connecters, and its leading object is to provide anelectrical connecter which will establish an effective frictional lockJoint between a service line and a supply line, by a conventional push-.and-pull operation.

It is the present common practice to operate vacuum cleaners, and otherelectrical equipment, by the use of a service cord, on the end of whicha connecter is attached. This connecter is usually provided with twometal prongs, which are spaced apart from each other, and connected withthe service wires of the cord inside of the plug. The prongs areinserted in a companion connecter, which may be in the form of a femalecord attachment, or a female wall attachment, or outlet. The frictionalcontact established between the male prongs and the female outlet deviceor attachment is usually sufficient to keep the service wires connectedwith the supply wires. But when any pulling strain is imposed on thesupply cord, caused by the moving of the vacuum device or otherelectrical unit from onepart of a room to another, the prongs frequentlypull out, thus separating the supply wires from the service wires.

This pulling strain, which frequently develops upon all service cordconnecters, also tends to loosen the terminals of the service wires,which are connected by short binding screws with the ends of theconnecting prongs, or pull toward each other,'with the result that shortcircuit connections between the supply wires are thereby established,and fuse plugs blown out, thus rendering the local service line dead.

The present invention relates to a connecter which includes male prongs,which have a resilient clutching action against the female outletdevice, and a screw plug which carries these prongs and which isthreaded in a holder so that pressure is maintained on the terminals ofthe supply wires, to resist separation from each other, under pullingeffort upon the service cord, thereby avoiding short circulting of thesupply current wires.

With the above and other objects in view the invention relates to newand useful combinations, constructions, and arrangements of parts,clearly described in the following specification, and fully illustratedin the accompanying drawing, in which:-

Fig. 1 is a side elevation of the connecter shown united to a screw plugmember adapted to engage a socket outlet device.

r Fig. 2 is a side elevation of the connecter removed.

Fig. 3 is a longitudinal sectional view thereof, on an enlarged scale.

Fig. 4 is an end view of the inner end of the connecter. I r

Fig. 5 is an end view of the screw plug removed 5 from the body of theconnecter, showing the inner end of the screw plug.

Fig. 6 is a side elevation of one of the clutch prongs, on an enlargedscale, showing the same open before being mounted in place. 10

Fig. 7 is a similar side elevation, partly in section, of a modifiedform.

Referring to the accompanying drawing illustrating the practicalembodiment of my invention 5 designates the body of the connecter, whichconsists of an inner end 6 having a circular socket I, the wall of whichis formed with an internal screw thread 8. The body 5 also provides aconical shank ii, havinga terminal integral bead i0, so that the devicemay be readily pulled when in place.

The service cord ii extends through the shank 9 and the wires i2 and i3thereof are knotted at H and thence diverge outwardly to engage thebinding screws I5 and i6, winch are threaded into the female screws l5a.and i6a, embedded in the detachable screw plug H, which is externallyscrew threaded to engage the female screw threads 8, of the body 5.

The screw plug ll carries the metal clutch prongs i8 and I9, which arespaced apart and insulated from each other by the material of which thescrew plug is composed. The inner end of the clutch prong i8 is formedwith a lateral holding arm lBa; andthe inner end of the clutch prong i9is formed with a lateral holding arm Ho. The holding arms i8a and Miaare provided with holes to receive the binding screws i5 and i6.

Each clutch prong consists of a strip of spring metal, which is foldedupon itself to provide resilient sides 20 and 2|, between which a stripof resilient rubber 22, or other tension creating material, is placed.This material is placed under compression when the prong is forced intothe female slot of the outlet connecting plug or device. Theintermediate strip or layer of rubber or other compressible material isextended to the upper end of the prong, so that each prong is providedwith a lateral holding arm consisting of relatively yieldable parts,betweenwhich a layer of thin resilient rubber or other material isdisposed. This provides a binding post clamping action which insuresspring tension on the terminals of the service wires which are clampedto the clutch prongs.

The screw plug i1 is threaded into the socket i so that the heads of thebinding screws are pressed tightly against the end wall 1a of thesocket, thereby holding the terminals of the service wires againstaccidental detachment from the binding screws.

The body is formed with a knot pocket Ia, so that any pulling strainimposed on the service cord will not be directly transmitted to theterminals of the service wires.

In Fig. 7, I show a modified form oi the clutch prong, wherein theintermediate layer of rubber is eliminated. This prong consists of asingle strip of spring metal which is folded upon itself to providecompanion legs 23 and 24, united at the bend 25. The leg 28 is formedwith a series of recesses 23a, which form a plurality of spacedcontacting points 231) to engage the opposing side of the leg 24, sothat the leg 23 can be forced under pressure to yield relative to thecompanion leg 24. The upper ends of the legs 28 and 24 form the two partholding arm 26, which is pierced by holes to receive the binding screw.The action of this clutch prong is similar to that of the rubberequipped clutch prong.

In practice I have found that my improved service connecting plug willhold connection with an outlet, even though the adjacent portion of theservice cord is subject to a bending action of approximately sixtydegrees.

But in the event it is desired to separate the service connection theclutch prongs will pull out when a proper pulling effort is applied onthem.

Having described my invention I claim:-

1. An electrical connecter consisting of a plug having a socket formedin one end thereof, said socket providing an annular wall having aninternal screw thread and a knot receiving recess, a circular disc screwthreaded in said wall and provided with transverse openings spacedlaterally from each other, a pair of prongs extending through saidopenings, each prong consisting of a strip of resilient metal foldedupon itself to provide relatively movable spring legs, means between thelegs adapted to be compressed to produce a clutch-like action of theprong in a receiving socket plug, each prong also having out-turned endsdisposed against the inner side of said plug, and screws extendingthrough said out-turned ends into thedisc to hold said prongs againstrelative movement in said disc, the disc when threaded into the plugserving to retain the screws against displacement therein to hold anyconnected wires in place.

2. The construction set forth in claim 1, the means between the legs ofthe prongs consisting of resilient rubber strips.

3. An electrical connecter consistingof a plug having a cylindricalsocket in one end thereof providing an annular wall having an internalscrew thread and a shoulder at the inner end of the socket, said plughaving a central pull handle integral with the socket and provided withan electrical cord opening registering with the socket and with a knotreceiving recess between said socket and said opening, a circular discthreaded on said wall into said socket, said disc having a pair oftransversely spaced openings and electrical conductor prongs extendingthroughsaid openings in spaced relation to each other, each prong havinga lateral inner end disposed against the inner surface of the disc and ascrew extending through each of said lateral ends and having threadedengagement with the disc to positively clamp its prong thereto, the discbeing adapted to be threaded in said socket whereby the inner ends ofsaid screws will be forced against the shoulder of said plug to lock thescrews against accidental turning movement in said disc.

VINCENT POLIMENI.

